Respiratory arrest is caused by apnea (cessation of breathing) or respiratory dysfunction severe enough it will not sustain the body (such as agonal breathing). Prolonged apnea refers to a patient who has stopped breathing for a long period of time. If the heart muscle contraction is intact, the condition is known as respiratory arrest. An abrupt stop of pulmonary gas exchange lasting for more than five minutes may damage vital organs especially the brain, possibly permanently. Lack of oxygen to the brain causes loss of consciousness. Brain injury is likely if respiratory arrest goes untreated for more than three minutes, and death is almost certain if more than five minutes.
Respiratory arrest can be used interchangeably with complete respiratory failure. The former refers to the complete cessation of breathing, while respiratory failure is the inability to provide adequate ventilation for the bodyís requirements. However, both lead to death without intervention. Respiratory arrest is also different from cardiac arrest, the failure of heart muscle contraction. If untreated, one may lead to the other.
A condition that frequently precedes respiratory arrest is respiratory distress, which is a gradual, subtle imbalance in patient response that can result in eventual respiratory failure and arrest. Symptoms of respiratory compromise can differ with each patient. Complications from respiratory compromise are increasing rapidly across the clinical spectrum, partly due to expanded use of opioids combined with the lack of standardized guidelines among medical specialties. While respiratory compromise creates problems that are often serious and potentially life-threatening, they are almost always preventable with the proper tools and approach. Appropriate patient monitoring and therapeutic strategies are necessary for early recognition, intervention and treatment.
Before respiratory arrest officially occurs, patients may experience some neurologic dysfunctions, such as feeling agitated, confused, and struggling to breathe. Tachycardia, sweating, intercostal retractions, and sternoclavicular retractions may occur as well. Patients who have an impaired central nervous system or respiratory muscle weakness may experience irregular patterns of respiration and feeble, gasping attempts to breathe. Patients who developed respiratory arrest from the cause of a foreign body in the airway may choke, call the attention of people nearby to their neck, and give out a harsh sound. By monitoring a patientís oxygen and carbon dioxide levels, practitioners can prepare for ensuing respiratory arrests in patients. Infants that are under three months may develop respiratory arrest without any signs of warning and must be carefully taken care of. The development of respiratory arrest could come from infection, metabolism disorders, or respiratory fatigue. Another group of patients that should be on the watch list are asthmatics or patients with other chronic lung diseases. They can be become hypercapnic or tired after bouts of respiratory distress. These symptoms will lead to apnea without any signs of warning.
Diagnosis requires clinical evaluation. If there was a foreign body obstructing the airway, the first option would be to locate the foreign body. The presence of a foreign body can be detected from resistance to ventilation from the mouth-to-mask or bag-valve-mask ventilation. The foreign body can be extracted during laryngoscopy for endotracheal intubation.
Resistance to bag valve mask may suggest presence of a foreign body that is obstructing airways and commonly used as a diagnostic tool and treatment for respiratory arrest. The bag-valve-mask device has a self-inflating bag with a soft mask that rests on the face. When the bag is connected to an oxygen supply, the patient will receive 60 to 100% of inspired oxygen. The purpose of bag-valve-mask is to provide adequate temporary ventilation and allow the body to achieve airway control by itself. However, if the bag-valve-mask is left on for more than five minutes, air may be introduced into the stomach. At that point, a nasogastric tube should be inserted to take the accumulated air out. During this process, practitioners must carefully position and maneuver the bag-valve-mask in order to keep airways open. An oropharyngeal airway is used during bag-valve-mask ventilation to prevent oropharynx soft tissues from blocking the airway. An oropharyngeal airway may cause gagging and vomiting. Therefore, an oropharyngeal airway must be sized appropriately. It should be as long as distance between corner of patientís mouth and angle of the jaw is calculated correctly. For children, pediatric bags can be used. Pediatric bags have a valve that limits peak airway pressures to around 35Ė40 cm of water. Practitioners must tweak valve settings to accurately determine each of their patients to avoid hypoventilation or hyperventilation.
The laryngeal mask airway (LMA) is a tube with an inflatable cuff. A laryngeal mask airway can be positioned in the lower oropharynx to prevent airway obstruction by soft tissues and to create a safe channel for ventilation. The laryngeal mask airway is the standard rescue ventilation when endotracheal intubation cannot be accomplished. To insert the laryngeal mask airway into the patient, the deflated mask should be pressed against the hard palate, rotated past the base of the tongue, and reaching the pharynx. Once the mask has been placed in the correct position, the mask can be inflated. Some benefits of the laryngeal mask airway include minimization of gastric inflation and protection against regurgitation. A potential problem the laryngeal mask airway poses is that over inflation will make the mask more rigid and less able to adapt to the patientís anatomy, compressing the tongue and causing tongue edema. In that case, the mask pressure should be lowered or a larger mask size should be used. If non-comatose patients are given muscle relaxants before the insertion of the laryngeal mask airway, they may gag and aspirate when the drugs are worn off. At that point, the laryngeal mask airway should be removed immediately to eliminate the gag response and buy time to start at new alternative intubation technique.